Multilayer Ceramic Capacitor Design for Creeping Discharge Reduction

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Solution Overview

Problem

Existing multilayer ceramic electronic components face challenges with creeping discharge at high voltages, and existing solutions like film capacitors are not suitable for surface-mountable designs due to size constraints and insufficient creeping distances.

Innovation Solution

A multilayer ceramic electronic component design featuring a plurality of ceramic bodies with metal terminals and a cover material, where the ceramic bodies have a specific dimensions and orientation to reduce creeping discharge, allowing for surface-mountable and compact designs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If film capacitors are used to increase creeping distance, then creeping discharge is reduced, but the component size cannot be reduced and lead terminals are required

Engineering Contradiction:

Improvecreeping discharge resistanceVSAvoidcomponent size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The capacitor is divided into multiple unit capacitors arranged in a matrix pattern, where each unit has its own outer electrodes. This segmentation allows the creeping distance to be distributed across multiple smaller units rather than requiring a single large structure, enabling reduced overall component size while maintaining adequate creeping distance for high-voltage operation

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single-layer structure to a multilayer configuration with multiple ceramic layers stacked vertically. By utilizing the vertical dimension (height direction) to arrange multiple capacitor units, the design achieves sufficient creeping distance through the layered structure without increasing the horizontal footprint, thus reducing overall component size while maintaining reliability

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If film capacitors are used to increase creeping distance, then creeping discharge is reduced, but lead terminals are required for mounting

Engineering Contradiction:

Improvecreeping discharge resistanceVSAvoidmounting structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the capacitor structure with surface-mountable terminals by providing external electrodes directly on the outer surfaces of the multilayer ceramic body. These external electrodes can be directly soldered to circuit boards without requiring separate lead terminals, simplifying the mounting structure while maintaining the multilayer configuration needed for adequate creeping distance

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention replaces the mechanical lead terminal system with an electrical connection system using external electrodes formed directly on the ceramic body. This substitution eliminates the need for separate lead wires and their mechanical attachment structures, reducing device complexity while maintaining adequate insulation and creeping distance through the ceramic material and electrode arrangement

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If capacitor size is reduced for surface-mountable design, then mounting efficiency is improved, but creeping distance becomes insufficient

Engineering Contradiction:

Improvemounting efficiencyVSAvoidcreeping discharge resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The invention utilizes the vertical dimension by stacking multiple ceramic layers to achieve sufficient creeping distance without increasing horizontal dimensions. This multilayer approach allows the component to maintain a compact footprint suitable for surface-mounting while providing adequate creeping path length through the vertical arrangement of electrodes and dielectric layers

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

By segmenting the capacitor into multiple small unit capacitors arranged in a matrix, each unit contributes to the overall creeping distance. The segmented structure allows the total creeping path to be distributed across multiple units, enabling sufficient creeping distance in a compact overall package that maintains high mounting efficiency

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11527364B2Multilayer ceramic electronic component including a plurality of bodies and metal terminals connected to outer electrodes

Publication Date: 2022.12.13 MURATA MFG CO LTD

AI summary

A multilayer ceramic electronic component includes multilayer ceramic electronic component bodies which each include a multilayer body and first and second outer electrodes provided on both end surfaces of the multilayer body. The multilayer ceramic electronic component also includes a first metal terminal connected to the first outer electrodes and a second metal terminal connected to the second outer electrodes. Each multilayer ceramic electronic component body includes a dimension in a lamination direction that is less than a dimension in a width direction, and is positioned so that one of the first and second side surfaces faces a mounting surface. The first and second metal terminals extend between the first and second outer electrodes of the multilayer ceramic electronic component bodies. The multilayer bodies, first and second outer electrodes, and at least portions of the first and second metal terminals are covered by a cover material.